Interconnect Challenges and Carbon Nanotube as Interconnect in Nano VLSI Circuits

This chapter discusses about the behavior of Carbon Nanotube (CNT) different structures which can be used as interconnect in Very Large Scale (VLSI) circuits in nanoscale regime. Also interconnect challenges in VLSI circuits which lead to use CNT as interconnect instead of Cu, is reviewed. CNTs are classified into three main types including Single-walled Carbon Nanotube (SWCNT), CNT Bundle, and Multi-walled Carbon Nanotube (MWCNT). Because of extremely high quantum resistance of a SWCNT which is about 6.45 kΩ, rope or bundle of CNTs are used which consist of parallel CNTs in order to overcome the high delay time due to the high intrinsic (quantum) resistance. Also MWCNTs which consist of parallel shells, present much less delay time with respect to SWCNTs, for the application as interconnects. In this chapter, first a short discussion about interconnect challenges in VLSI circuits is presented. Then the repeater insertion technique for the delay reduction in the global interconnects will be studied. After that, the parameters and circuit model of a CNT will be discussed. Then a brief review about the different structures of CNT interconnects including CNT bundle and MWCNT will be presented. At the continuation, the time domain behavior of a CNT bundle interconnect in a driver-CNT bundle-load configuration will be discussed and analyzed. In this analysis, CNT bundle is modeled as a transmission line circuit model. At the end, a brief study of stability analysis in CNT interconnects will be presented

A Review of Electronic Band Structure of Graphene and Carbon Nanotubes Using Tight Binding

The electronic band structure variations of single-walled carbon nanotubes (SWCNTs) using Huckle/tight binding approximation theory are studied. According to the chirality indices, the related expressions for energy dispersion variations of these elements are derived and plotted for zigzag and chiral nanotubes

COX inhibition: Catalepsy and Striatum Dopaminergic-GABAergic-Glutamatergic Neurotransmission

Selective COX-2 and COX-1 inhibitors were administered (i.p. acutely) to normal and parkinsonian rats, followed by the analysis of the striatal dopamine, GABA and glutamate concentrations using the microdialysis technique, simultaneously, the catalepsy of animals was evaluated. Selective COX-2 inhibition showed improving effects on the catalepsy followed by decreasing the striatum glutamatergic-GABAergic and enhancing the dopaminergic neurotransmission. Nonetheless COX inhibition had no significant improving effects on damaged Substantia Nigra Pars Compacta (SNc) neurons

Comparación de los rendimientos del maíz, empleo de agua y crecimiento bajo diferentes sistemas de laboreo y tipos de fertilizantes

Contexto: EL maíz es uno de los cuatro cereales más importantes después del trigo y el arroz. El nitrógeno y variadas formas de laboreo son factores importantes para mejorar los rasgos y el rendimiento del maíz. La agricultura sostenible requiere de mejoras en cuanto al manejo del laboreo de los suelos, así como una aplicación más eficiente de los fertilizantes como recursos agrícolas. Objetivo: Esta investigación se enfocó en la importancia de realizar exámenes a las condiciones de los nutrientes, particularmente el consumo de nitrógeno en varios sistemas de laboreo, así como el impacto de estos factores en el rendimiento, crecimiento y eficiencia en el empleo del agua en el maíz cultivado en Irán. Métodos: El experimento se desarrolló en una parcela dividida, mediante un diseño experimental completamente aleatorio por bloques y cuatro réplicas, en la ciudad de Darreh shahr, provincia de Ilam, Irán. Los tratamientos consistieron en tres niveles de laboreo del suelo, incluyendo la siembra directa, mediante el laboreo combinado y surcos (arado Moldboard + gradas dobles + nivelador y surcos en la parcela principal). Resultados: Se demostró que la mayor cantidad de materia seca total se obtuvo en el tratamiento con mínimo laboreo (4542,7 g/m2), mientras que el menor valor se obtuvo mediante el cultivo tradicional (4029,2 g/m2). El volumen de fertilizante no utilizado (NPK)0 fue de 0,61 kg-m3. Se puede afirmar que el laboreo mínimo puede mejorar los rendimientos del maíz con el más alto EEA, y también puede incrementar sus propiedades durante la temporada de crecimiento. Conclusiones: Según los resultados de este estudio, se puede afirmar que el laboreo mínimo mejora los rendimientos del maíz con el más alto EEA, y también puede incrementar sus propiedades durante la temporada de crecimiento

Comparison of Corn Yield, Water Use Efficiency (WUE), and Growth under Different Tillage Systems and Fertilizer Inputs

Context: Corn is one of the four most important cereals in the world after wheat and rice. Nitrogen and various tillage systems are important factors in improving the traits and performance of corn. Sustainable agriculture requires improvements in soil tillage management and more efficient application of fertilizers as agricultural resources. Objective: Considering the importance of examining the status of nutrients, particularly nitrogen consumption in various tillage systems, and the impact of these factors on the performance, growth, and water use efficiency of corn in Iran, this research was conducted. Methods: The experiment was performed as a split plot in a randomized completely block design (RCBD) with four replications in Darreh shahr city, Ilam province, Iran. The treatments consisted of three levels of soil tillage including NT (direct sowing), MT (using compound tillage and furrow) and CT (Moldboard plow+ double discs + leveler and furrow) as the main plot. Results: The results showed that the highest total dry matter (TDM) was obtained in MT treatment at 4542.7 g/m2 and the lowest in CT treatment at 4029.2 g/m2. The amount of non-use of fertilizer (NPK)0 was 0.61 kg/m3. It can be stated that MT can improve the grain yield of corn with the highest WUE as well as increasing the properties during the growing season. Conclusions: Based on the results of this study, it can be stated that MT can improve maize grain yield with the highest WUE and increase the characteristics during the growing season

High-performance perovskite solar cell using photonic–plasmonic nanostructure

Abstract In this paper, a coupled optical-electrical modeling method is applied to simulate perovskite solar cells (PSCs) to find ways to improve light absorption by the active layer and ensure that the generated carriers are collected effectively. Initially, a planar structure of the PSC is investigated and its optical losses are determined. To reduce the losses and enhance collection efficiency, a convex light-trapping configuration of PSC is used and the impacts of these nanostructures on all parts of the cell are investigated. In this convex nanostructured PSC, the power conversion efficiency (PCE) is found to be increased when the thickness of the absorbing layer remained unchanged. Then, a plasmonic reflector is applied to trap light inside the perovskite. In this structure, by scattering light through the surface plasmon resonance (SPR) effect of the Au back-contact, the electromagnetic field is found to concentrate in the active layer. This results in increased perovskite absorption and, consequently, a high current density of the cell. In the final structure, which is the integration of these two structures, optical losses are found to be greatly diminished and the short-circuit current density (Jsc) is increased from 18.63 mA/cm2 for the planar structure to 23.5 mA/cm2 for the proposed structure. Due to the increased Jsc and open-circuit voltage (Voc) caused by the improved carrier collection, the PCE increases from 14.62 to 19.54%

Morphological investigation and 3D simulation of plasmonic nanostructures to improve the efficiency of perovskite solar cells

Abstract The light absorption process is a key factor in improving the performance of perovskite solar cells (PSCs). Using arrays of metal nanostructures on semiconductors such as perovskite (CH3NH3PbI3), the amount of light absorption in these layers is significantly increased. Metal nanostructures have been considered for their ability to excite plasmons (collective oscillations of free electrons). Noble metal nanoparticles placed inside solar cells, by increasing the scattering of the incident light, effectively increase the optical absorption inside PSCs; this in turn increases the electric current generated in the photovoltaic device. In this work, by calculating the cross-sectional area of dispersion and absorption on gold (Au) nanoparticles, the effects of the position of nanoparticles in the active layer (AL) and their morphology on the increase of absorption within the PSC are investigated. The optimal position of the plasmonic nanoparticle was obtained in the middle of the AL using a three-dimensional simulation method. Then, three different morphologies of nano-sphere, nano-star and nano-cubes were investigated, where the short-circuit currents (Jsc) for these three nanostructures were obtained equal to 19.01, 18.66 and 20.03 mA/cm2, respectively. In our study, the best morphology of the nanostructure according to the Jsc value was related to the nano-cube, in which the device power conversion efficiency was equal to 16.20%, which is about 15% better than the PSC with the planar architecture

Design of optimized photonic-structure and analysis of adding a SiO2 layer on the parallel CH3NH3PbI3/CH3NH3SnI3 perovskite solar cells

Abstract So far, remarkable achievements have been obtained by optimizing the device architecture and modeling of solar cells is a precious and very effective way to comprehend a better description of the physical mechanisms in solar cells. As a result, this study has inspected two-dimensional simulation of perovskite solar cells (PSCs) to achieve a precise model. The solution which has been employed is based on the finite element method (FEM). First, the periodically light trapping (LT) structure has been replaced with a planar structure. Due to that, the power conversion efficiency (PCE) of PSC was obtained at 14.85%. Then, the effect of adding an SiO2 layer to the LT structure as an anti-reflector layer was investigated. Moreover, increasing the PCE of these types of solar cells, a new structure including a layer of CH3NH3SnI3 as an absorber layer was added to the structure of PSCs in this study, which resulted in 25.63 mA/cm2 short circuit current (Jsc), 0.96 V open circuit voltage (Voc), and 20.48% PCE